This invention relates to a sealing means for a control cable such as a push-pull cable and rod assembly which includes a push rod mountable remote from a device which is to be controlled by an operator at the remote site. In particular, it relates to a sealing capsule for a push rod associated with a control panel, the rod affixed to the end of a push-pull cable carried in a housing for control of a device such as an engine accessory in a vehicle or the like.
Push-pull cables are utilized quite frequently in the construction of equipment, particularly heavy earth working equipment to control the various engine and auxillary components of the vehicle. Operation of heavy equipment and the like results in dirt, and dust, and in freezing conditions ice settling on and about all portions of the equipment. Continued movement of push rods affixed to push-pull cables through fittings associating the control cable with an instrument panel causes wear and eventual failure in the sealing means associated with the push-pull cable fitting. In addition to failure of the sealing means, dirt, dust, ice and other deleterious material can work into the housing to cause early failure of the cable section of the push-pull cable. Accordingly, it is extremely important to keep the housing clear of foreign materials which may abrade or corrode the push-pull cable. In the past it has been the practise to provide push-pull cables as an assembled unit complete with housings and seals so that failure of the seal required complete replacement of the entire housing and the cable. This has proved burdensome and expensive to the operator.
One of the problems in push-pull cable assemblies is the removal of ice formed about the push rod portion extending outwardly of the fitting and cable housing. The problem has been so severe in the past that vehicle operation may be degraded. Normal elastomeric seals used to prevent dirt, dust and liquids from entering the housing have proved inadequate to remove ice since the ice will tear away the elastomeric seal. The addition of metal scrapers to the push rod seal assembly is in part satisfactory; however, when the ice is heavy and completely surrounds the push rod it is difficult if not impossible to break away the ice from the push rod by conventional scraper methods.
In addition to the above problems push-pull cable assemblies have been formed so that oil can be retained in the housing to prevent corrosion and reduce problems caused by dirt and other deleterious material reaching the interior of the housing. Since the affixed cable to the push rod of the push-pull cable assembly generally has a smaller diameter than the push rod itself, motion of the push rod in and out of the housing through the seal may act to "pump" the oil outwardly of the assembly, particularly if the oil is inserted with the push rod in the extended position. This "pumping" may introduce air and other matter into the push rod assembly with problems ensuing therefrom.